Boring-bar.



D. H. SHATTUCK.

BORING BAR.

APPLICATION FILED SEPT. 23, 1907.

360 Patented May 18, 19%.

Mhmasmem I Wag W 4/44 M .m;%m@ g u ,DAVID H. SHAlTUCK, OF WESTFORD,MASSACHUSETTS.

BQRING-BAR.

No. ceases.

Specification of Letters Patent.

Patented an is,

Application filed September 23, 1907. Serial N 0. 394,123.

T 0 (133 whom it mag concern:

Be it known that I, Dav n H. SHA-TTUOK, a citizen of the United States,residing at W estford, in the county of MiddleseX and Commonwealth ofMassachusetts, have invented a certain new and useful Improvement inBoringdBars, of which the fol owing is a specification.

'lhis invention relates to boring bars or bars to which are securedcutters or cutting bits and adapted to be used in horizontal or verticalboring-mills or machines or in other usual ways.

The object of this invention is to rovide means for accurately anduickly a justing the cutters to bore holes of ill crent sizes and forrigidly holding the cutters without the use of set-screws or keys.

Hcretoforeit has been customary to use a single cutter in the bar bymeans of 'a key or set-screw. The driving'in of the key is. apt tospring the bar and to displace the cutter and where a set-screw isusedit is necessary to spot or to make a depression in the cutter toreteive the point of the screw, so that if the cutter is subsequentlyground, it is difficult to get a new spot or hole to receive theset-screw without materially reducing the size of the hole to be bored,that is, a very slight reduction of the cutting diameter of theboring-bar cannot be made. Sometimes a double-header or cutter shaped tocutat both ends and extending through the bar to an equaldistance fromthe center of the bar on each side is held in are many times reground. Iam also able to utilize ver short stock in the making of the cutters, tat is, pieces so short that they could not be utilized in cutter-barsheretofore. By the use of this cutter-bar without removing the cutters Ican vary the cutting 1 diameter within a considerable range, that is,

l-can reduce the cutting diameter and subequently enlarge said cuttingdiameter while retaining the same cutters.

' With the very hard tool-steel now much tened side 0 to fit the washerD, which used and sometimes called self-hardening steel it is im)ossible to spot the cutters or drill the holes for the reception of thesetscrew, such steel being affected only by grinding with emery or otherabrasives. 'lhis invention makes the use of cutters oi the mostrefractory steel feasible.

' In the accompanying drawing, Figure is, a side elevation of aboring-bar provided with my improvement, the shank or bar proper beingbroken out to save space in the drawing and the lower end of the bar be"in central vertical section on the line l-l Fig. 2:; Fig; 2, a plan ofthe bottom of the cutter-bar,- Fig. 3, a side elevation of the part ofthe bar which in Fig. 1 is shown in section.

. The bar proper A is of the usual form, ere.

the usual horizontal chucking machines.

In the lower or o erative end of the bar a I is arranged a centra holea, in which turns an adjusting screw-cone provided. with an ittefrmediate conical part 3), two extern: screw threaded portions 5 t anda cylindrical guiding sectionb which has a sliding fit in the hole a,the screw 5 engaging an iuternal screw-thread a in the hole a, and thescrew 5 receivingthe nut F named below. The outer end I) i lthisscrew-cone is square or many-sided to be engaged by a wrench. i

'lhe bar pro or A is provided with a plurality of radia c lindricalholes a lying in the same radial plhne at equal angular intervals fromeach other.

In the holes a are arranged cutters C having cylindrical shanks, theouter or cutting parts c of which be of anysuitable shape and the innerends 0 of whichare suitabl gr rounded or curved to allow the cone ll,witl'i which they are in contact, to move easily. The cutters are eachprovided with a l on said-flattened sides and is pressed against them bythe nut E, which turns on the ternally threaded reduced lower end ofshank or bar proper A, said nut it being represented as provided with aradial hole 6 to l. to

against the cone.

be engaged by a spanner or hand-s ike.

The amount of projection of the cutters rom the bar A is determined bythe diameter of the cone B where the inner ends'of said cut ters are incontact with said cone. When the nut E is-loosened, turning the cone Bfarther into the handle A throws" the cutters outward, but when the coneis turned in the other direction, the cutters are pushed in When thecone .B is adjusted to the proper osition to secure the desiredprojection of t e cutters, said cone is ternal screw-thread and havingradial cylindrical holes, shanks arranged in sa d holes and eachprovided with a flattened surface, and a nut arranged on said bar andadapted to enga e the flattened surfaces of said cutters to ho d thelatter.

' 2. The combination of a bar having radial cylindrical holes, cuttershaving cylindrical shanks arranged in said holes and each pro-' videdwith a flattened surface, said bar being provided with an annular grooveconcentric cutters having cylindrical withits axis and said grooveintersecting.-

said radial holes, and a nut arranged on said bar and in said groove andada ted to engage said flattened surfaces to hol said cutters.

In witness whereof, have'aflixed m signature in presence of twowitnesses.

, DAVID H. snArrUoK. Witnesses ALBERT M. Moonn, GRACE CROWLEY.

